alright, everybody writen one about this but nothing worked for me, here's how it works without any problem:
first run brew install supervisor
run brew services start supervisor
now to start supervisor, this will make sure supervisor runs at startup as well.
supervisor searches for configuration file in following paths: /usr/local/etc/supervisord.conf, /usr/local/supervisord.conf, supervisord.conf, etc/supervisord.conf, /etc/supervisord.conf, /etc/supervisor/supervisord.conf
we have to create one in order for it to work: